Difference between NSArray and NSMutableArray

NSMutableArray (and all other classes with Mutable in the name) can be modified. So, if you create a plain NSArray, you cannot change its contents later (without recreating it). But if you create an NSMutableArray, you can change it — you'll notice it has methods like -addObject: and -insertObject:atIndex:.

See the documentation for details.

The "mutable" types are classes which can be changed after they've been initialized, like NSMutableString vs NSString.

NSArray : in NSArray we can not change index.... Means fix array.

NSMutableArray : in NSMutableArray we can change index and also add the value in array at run-time..